I added a second account for gmail and the only option is "Sync Email".
On the first gmail account, I have "Sync Contacts" and "Sync Gmail", but not calendar sync.
When adding a new account, the options are "Corporate", "Email", and "Google". My first gmail account I added as "Google", the second gmail account was added as "Email". If I try to create a second account under "Email" or "Google", get a message that the account already exists.
Tried the Synker app/widget, but still don't see an option to sync calendar.
Solution: Used SDFormatter to remove all the partitions from the SD card, re-imaged the card, increased the partition size to 5 M on the 8 M card, copied the market files on, and now everything works great. Used the current nightly build (8/31/2011) and running the Nook Color at 1300 mhz with no issues.